Opens a stream for writing.


func CFWriteStreamOpen(_ stream: CFWriteStream!) -> Bool



The stream to open.

Return Value

true if stream was successfully opened, false otherwise. If stream is not in the CFStreamStatus.notOpen state, this function returns false.


Opening a stream causes it to reserve all the system resources it requires. If the stream can open in the background without blocking, this function always returns true. To learn when a background open operation completes, you can either schedule the stream into a run loop with CFWriteStreamScheduleWithRunLoop(_:_:_:) and wait for the stream’s client (set with CFWriteStreamSetClient(_:_:_:_:)) to be notified or you can poll the stream using CFWriteStreamGetStatus(_:), waiting for a status of or CFStreamStatus.error.

See Also

Opening and Closing a Stream